The Static and Fatigue Behavior of AlSiMg Alloy Plain, Notched, and Diamond Lattice Specimens Fabricated by Laser Powder Bed Fusion

Abstract

Abstract:The fabrication of engineered lattice structures has recently gained momentum due to the development of novel additive manufacturing techniques. Interest in lattice structures resides not only in the possibility of obtaining efficient lightweight materials, but also in the functionality of pre-designed architectured structures for specific applications, such as biomimetic implants, chemical catalyzers, and heat transfer devices. The mechanical behaviour of lattice structures depends not only the composition of the base material, but also on the type and size of the unit cells, as well as on the material microstructure resulting from a specific fabrication procedure. The present work focuses on the static and fatigue behavior of diamond cell lattice structures fabricated from an AlSiMg alloy by laser powder bed fusion technology. In particular, the specimens were fabricated with three different orientations of lattice cells-[001], [011], [111]-and subjected to static tensile testing and force-controlled pull-pull fatigue testing up to 1 × 10 7 cycles. In parallel, the mechanical behavior of fully dense plain and notched tensile specimens was also studied and compared to that of their lattice counterparts. Results showed a significant effect of the cell orientation on the fatigue lives: specimens oriented at [001] were~30% more fatigue-resistant than specimens oriented at [011] and [111].

Mechanical properties of diamond lattice Ti–6Al–4V structures produced by laser powder bed fusion: On the effect of the load direction

“…On the other side, the anisotropic behavior of diamond based meta-materials was reported by Soul et al [21], partially confirming what Xie et al [18] evaluated numerically. This is in line with the quasi-static tests results of the present study.…”

“…Despite the mentioned differences, this study presents similarities with the work of Soul et al [21] especially as far as the failure mechanisms on macroscopic level are concerned. The three different batches present the same orientation of the slip planes as indicated by Soul et al.…”

“…When comparing the results of the present study with the work of Soul et al [21], some differences in production and testing methods are to be mentioned. Soul et al used a different material (i.e.…”

“…From an experimental point of view, Wauthle et al [20] explored the effect of build orientation on microstructure and compressive mechanical properties of additively manufactured Ti-6Al-4V lattice structures concluding that the diamond unit cell can be considered isotropic since the effect of the unit cell orientation cannot be distinguished in the mechanical properties. A similar study but with different results, was conducted by Soul et al [21] in which the mechanical behavior of Al-Si-10Mg lattice structures has been evaluated. In particular, Soul et al reported a significant impact of the diamond unit cell orientation with respect to the loading direction on the mechanical properties both in monotonic and cyclic conditions.…”

Mechanical properties and fluid permeability of gyroid and diamond lattice structures for intervertebral devices: functional requirements and comparative analysis

“…Among the three main diamond cell orientations: [001], [011] and [111], the [001] is selected, since it displays a more constant cross-sectional area along the vertical direction, thus reducing the stress riser effect and improving the tensile fatigue resistance of the structure [54]. Although some recent works study the impact of the gyroid orientation on its stiffness and strength [55][56][57], they present conflicting results, therefore the gyroid structure orientation is kept by default, and is determined by the governing equation used for its generation (Equation ( 6)):…”